The invention relates to a technique for discriminating a kind or type of loaded optical disk in an optical disk apparatus in which a plurality of kinds of optical disks are loaded.
In the case where the reproduction is interrupted when a movie, music, or the like is being reproduced by an optical disk apparatus and the reproduction is executed again, it is desirable that the reproduction can be promptly started.
In a conventional method of discriminating the kind of disk, there is such a problem that a time which is necessary to move an expander lens and a time which is necessary to vertically move an objective lens in the focusing direction are long, so that a time which is required to discriminate the kind of disk is long. Therefore, a method whereby the kind of disk which has previously been reproduced is stored into a memory has been proposed. For example, refer to JP-A-2000-187927 (pages 2 to 4, FIG. 2).